linux.git/fs/ext4/fast_commit.c, branch v6.6.131

ext4: fix iloc.bh leak in ext4_fc_replay_inode() error paths

2026-04-02T11:07:29+00:00

commit ec0a7500d8eace5b4f305fa0c594dd148f0e8d29 upstream.

During code review, Joseph found that ext4_fc_replay_inode() calls
ext4_get_fc_inode_loc() to get the inode location, which holds a
reference to iloc.bh that must be released via brelse().

However, several error paths jump to the 'out' label without
releasing iloc.bh:

 - ext4_handle_dirty_metadata() failure
 - sync_dirty_buffer() failure
 - ext4_mark_inode_used() failure
 - ext4_iget() failure

Fix this by introducing an 'out_brelse' label placed just before
the existing 'out' label to ensure iloc.bh is always released.

Additionally, make ext4_fc_replay_inode() propagate errors
properly instead of always returning 0.

Reported-by: Joseph Qi 
Fixes: 8016e29f4362 ("ext4: fast commit recovery path")
Signed-off-by: Baokun Li 
Reviewed-by: Zhang Yi 
Reviewed-by: Jan Kara 
Link: https://patch.msgid.link/20260323060836.3452660-1-libaokun@linux.alibaba.com
Signed-off-by: Theodore Ts'o 
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman

ext4: get rid of ppath in ext4_ext_insert_extent()

2026-03-25T10:05:32+00:00

[ Upstream commit f7d1331f16a869c76a5102caebb58e840e1d509c ]

The use of path and ppath is now very confusing, so to make the code more
readable, pass path between functions uniformly, and get rid of ppath.

To get rid of the ppath in ext4_ext_insert_extent(), the following is done
here:

 * Free the extents path when an error is encountered.
 * Its caller needs to update ppath if it uses ppath.
 * Free path when npath is used, free npath when it is not used.
 * The got_allocated_blocks label in ext4_ext_map_blocks() does not
   update err now, so err is updated to 0 if the err returned by
   ext4_ext_search_right() is greater than 0 and is about to enter
   got_allocated_blocks.

No functional changes.

Signed-off-by: Baokun Li 
Reviewed-by: Jan Kara 
Reviewed-by: Ojaswin Mujoo 
Tested-by: Ojaswin Mujoo 
Link: https://patch.msgid.link/20240822023545.1994557-15-libaokun@huaweicloud.com
Signed-off-by: Theodore Ts'o 
Stable-dep-of: 22784ca541c0 ("ext4: subdivide EXT4_EXT_DATA_VALID1")
Signed-off-by: Sasha Levin

ext4: increase IO priority of fastcommit

2025-11-24T09:29:44+00:00

[ Upstream commit 46e75c56dfeafb6756773b71cabe187a6886859a ]

The following code paths may result in high latency or even task hangs:
   1. fastcommit io is throttled by wbt.
   2. jbd2_fc_wait_bufs() might wait for a long time while
JBD2_FAST_COMMIT_ONGOING is set in journal->flags, and then
jbd2_journal_commit_transaction() waits for the
JBD2_FAST_COMMIT_ONGOING bit for a long time while holding the write
lock of j_state_lock.
   3. start_this_handle() waits for read lock of j_state_lock which
results in high latency or task hang.

Given the fact that ext4_fc_commit() already modifies the current
process' IO priority to match that of the jbd2 thread, it should be
reasonable to match jbd2's IO submission flags as well.

Suggested-by: Ritesh Harjani (IBM) 
Signed-off-by: Julian Sun 
Reviewed-by: Zhang Yi 
Reviewed-by: Jan Kara 
Message-ID: <20250827121812.1477634-1-sunjunchao@bytedance.com>
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: use handle to mark fc as ineligible in __track_dentry_update()

2024-10-10T09:57:49+00:00

commit faab35a0370fd6e0821c7a8dd213492946fc776f upstream.

Calling ext4_fc_mark_ineligible() with a NULL handle is racy and may result
in a fast-commit being done before the filesystem is effectively marked as
ineligible.  This patch fixes the calls to this function in
__track_dentry_update() by adding an extra parameter to the callback used in
ext4_fc_track_template().

Suggested-by: Jan Kara 
Signed-off-by: Luis Henriques (SUSE) 
Reviewed-by: Jan Kara 
Link: https://patch.msgid.link/20240923104909.18342-2-luis.henriques@linux.dev
Signed-off-by: Theodore Ts'o 
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman

ext4: fix fast commit inode enqueueing during a full journal commit

2024-10-10T09:57:48+00:00

commit 6db3c1575a750fd417a70e0178bdf6efa0dd5037 upstream.

When a full journal commit is on-going, any fast commit has to be enqueued
into a different queue: FC_Q_STAGING instead of FC_Q_MAIN.  This enqueueing
is done only once, i.e. if an inode is already queued in a previous fast
commit entry it won't be enqueued again.  However, if a full commit starts
_after_ the inode is enqueued into FC_Q_MAIN, the next fast commit needs to
be done into FC_Q_STAGING.  And this is not being done in function
ext4_fc_track_template().

This patch fixes the issue by re-enqueuing an inode into the STAGING queue
during the fast commit clean-up callback when doing a full commit.  However,
to prevent a race with a fast-commit, the clean-up callback has to be called
with the journal locked.

This bug was found using fstest generic/047.  This test creates several 32k
bytes files, sync'ing each of them after it's creation, and then shutting
down the filesystem.  Some data may be loss in this operation; for example a
file may have it's size truncated to zero.

Suggested-by: Jan Kara 
Signed-off-by: Luis Henriques (SUSE) 
Reviewed-by: Jan Kara 
Link: https://patch.msgid.link/20240717172220.14201-1-luis.henriques@linux.dev
Signed-off-by: Theodore Ts'o 
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman

ext4: fix incorrect tid assumption in ext4_fc_mark_ineligible()

2024-10-10T09:57:47+00:00

commit ebc4b2c1ac92fc0f8bf3f5a9c285a871d5084a6b upstream.

Function jbd2_journal_shrink_checkpoint_list() assumes that '0' is not a
valid value for transaction IDs, which is incorrect.

Furthermore, the sbi->s_fc_ineligible_tid handling also makes the same
assumption by being initialised to '0'.  Fortunately, the sb flag
EXT4_MF_FC_INELIGIBLE can be used to check whether sbi->s_fc_ineligible_tid
has been previously set instead of comparing it with '0'.

Signed-off-by: Luis Henriques (SUSE) 
Reviewed-by: Jan Kara 
Link: https://patch.msgid.link/20240724161119.13448-5-luis.henriques@linux.dev
Signed-off-by: Theodore Ts'o 
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman

ext4: fix possible tid_t sequence overflows

2024-09-12T09:11:37+00:00

[ Upstream commit 63469662cc45d41705f14b4648481d5d29cf5999 ]

In the fast commit code there are a few places where tid_t variables are
being compared without taking into account the fact that these sequence
numbers may wrap.  Fix this issue by using the helper functions tid_gt()
and tid_geq().

Signed-off-by: Luis Henriques (SUSE) 
Reviewed-by: Jan Kara 
Reviewed-by: Harshad Shirwadkar 
Link: https://patch.msgid.link/20240529092030.9557-3-luis.henriques@linux.dev
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: don't track ranges in fast_commit if inode has inlined data

2024-08-03T06:53:54+00:00

[ Upstream commit 7882b0187bbeb647967a7b5998ce4ad26ef68a9a ]

When fast-commit needs to track ranges, it has to handle inodes that have
inlined data in a different way because ext4_fc_write_inode_data(), in the
actual commit path, will attempt to map the required blocks for the range.
However, inodes that have inlined data will have it's data stored in
inode->i_block and, eventually, in the extended attribute space.

Unfortunately, because fast commit doesn't currently support extended
attributes, the solution is to mark this commit as ineligible.

Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1039883
Signed-off-by: Luis Henriques (SUSE) 
Tested-by: Ben Hutchings 
Fixes: 9725958bb75c ("ext4: fast commit may miss tracking unwritten range during ftruncate")
Link: https://patch.msgid.link/20240618144312.17786-1-luis.henriques@linux.dev
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: use ext4_fc_tl_mem in fast-commit replay path

2023-02-09T15:43:23+00:00

To avoid 'sparse' warnings about missing endianness conversions, don't
store native endianness values into struct ext4_fc_tl.  Instead, use a
separate struct type, ext4_fc_tl_mem.

Fixes: dcc5827484d6 ("ext4: factor out ext4_fc_get_tl()")
Cc: Ye Bin 
Signed-off-by: Eric Biggers 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20221217050212.150665-1-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o

jbd2: switch jbd2_submit_inode_data() to use fs-provided hook for data writeout

2022-12-09T02:49:25+00:00

jbd2_submit_inode_data() hardcoded use of
jbd2_journal_submit_inode_data_buffers() for submission of data pages.
Make it use j_submit_inode_data_buffers hook instead. This effectively
switches ext4 fastcommits to use ext4_writepages() for data writeout
instead of generic_writepages().

Signed-off-by: Jan Kara 
Link: https://lore.kernel.org/r/20221207112722.22220-9-jack@suse.cz
Signed-off-by: Theodore Ts'o